Bio: Amos Nur is widely considered to be one of the world’s top academic authorities on rock physics. He applies rock physics results to the understanding of tectonophysical processes in the Earth’s crust and lithosphere, with an emphasis on the role of fluids in crustal processes and in energy resources. Nur pioneered the use of seismic velocity measurements to characterize the changing state of oil and gas reservoirs as the volume of fluid in the rock changed during pumping; the process has come to be known as “four-dimensional” seismic monitoring. He has published over 240 papers and mentored dozens of doctoral and master’s candidates. Professor Nur was on the Stanford faculty from 1970 until his retirement in 2008 and he remains affiliated with the school as Professor Emeritus.
Abstract: In 1975 Frank Press suggested that we (USA, Japan, China, and the former USSR) will predict short and long-term earthquakes within 10 years (given sufficient funding). However, in 2013 (38 years later) Seiya Uyeda in Japan published a scathing paper about the lack of work on short-term earthquake prediction in Japan and actually elsewhere (in part at least for lack of funding for research). Because there was no real progress during these years many geophysicists concluded that earthquakes are actually not predictable. However, it is my opinion that we do not understand enough about the physics of earthquakes and especially the kind of possible precursors that are the key to short-term prediction. And the key to uncovering such possible precursors lies in rock physics.
In this talk, I will provide an updated review of what we know TODAY in rock physics that could be responsible for possible time-dependent changes in the crust prior to earthquakes. These include
- Effect of pressure
- Effects of stress-induced anisotropy
- Effects of saturation/partial saturation
- Intrinsic anisotropy
- Pressure solution and reactive fluids
With application to issues of
- Vertical crustal fault zones and low-velocity zones
- Post-earthquake velocity changes
- Pre-earthquake velocity changes
- Attenuation (1/Q)
- Electrical conductivity
- Elastic moduli
- Critically stressed crust